Radial air compressor



March 6, 1951 w. T. Mlxsl-:LL

RADIAL AIR COMPRESSOR Filed April 13, 1948 Patented Mar. 6, 1951 UNITEDSTATES PATENT OFFICE RADIAL AIR. COMPRESSOR Ward T. Mixsell, Washington,D. C.

Application April 13, 1948, Serial No. 20,699

(Cl. B30-130) 2 Claims. l

This invention relates to improvements in radial air compressors orpumps such as of a type which may be used for supplying compressed airto gas turbines for aeronautical services and in other environments Iinwhich such radial air compressors are adapted to be used.

Radial air compressors at present are generally of two types, first, thefree flow type in which air is moved by the impellers and is dischargedinto a circular chamber and in the case of multistage machines from thechamber to the inlet of the succeeding set of impellers, or secondly,the air is discharged from the impellers against vanes, whereby the flowis partially reversed, thereby converting the kinetic energy into staticpressure. this type being much more eilicient, when operating a fullvolume capacity, and designed pressure, but unlike the free flow type,if the delivery volume is reduced higher pressures occur which reactagainst the flow from the impellers thereby setting up pulsations andvibrations, which are harmful to the compressor and driving member.

My invention is directed to improvements in radial compressors of thefree flow type, with a variable volume delivery, said compressorcontaining means to arrest the circulatory motion of air beingdischarged, thus converting the same into static pressure. Thus, thecompressor is provided with diverters to direct the air tangentially andthereby stop the circular or rotary motion of the air. and further thecompressor is provided with defiectors to redirect the flow of airtoward the inlet of the succeeding impeller, so that the mass is broughtto a practical state of rest and a higher pressure obtains at that area,and thereby permits volumetric variations, without back pressurereactions. Also by discharging the air tangentially, I eliminate theouter space surrounding the vanes, such a space being common incompressors of this type, and can thereby reduce the outer diameter ofthe compressor by twice that space, with a corresponding reduction inweight.

In order to reduce the overall length of the compressor, I turn theimpeller outlets back upon themselves, while still retaining ample spacefor air to enter the same, so that lit will be possible to use four orfive stages in the same length where it was heretofore required to beable to use only three or four stages, thereby reducing the pressurerise in each stage, which will increase the eiciency, and also red'ucethe required diameter of the impellers and the entire machine.

A further improvement is in the method of constructing the entire unit.Usually multistage pumps and compressors are built split horizontally,being made from two castings and held together by flanges and aplurality of bolts, whereas I use a cylinder of high tensile material,as for example a shell, provided with separator rings, said ringssubdlviding the chambers, and the rings can be made of cast aluminummachined to t in the cylinder, the same having a flange in close runningcontact with the shroud of the impeller to prevent air leakage, thediverters and deflectors are a part of the same ring and can be of onecasting, the ring being held in proper position by dowels or set screws.The heads preferably are made of pressed steel and are identical, andcan be welded to the cylindrical shell.

Another improvement is in the shaft carrying the impellers which ispreferably made hollow, thereby to pass cold air through the same tocool the bearings in which the shaft is mounted, if desired.

A further object is to provide at the discharge end of the compressor abearing which carries the shaft and also a packing gland outside of thebearing thus preventing air and oil leakage, the packing also beinglubricated by the oil in the reservoir. At the inlet end a bearingcarries the shaft and then another bearing which takes the pressurethrust against the impellers, this bearing having an adjustable memberto regulate the clearance between the rotating impellers, and theflanges of the separators.

The invention is not intended to be limited to the exact constructionshown, but is capable of various modifications and forms, theaccompanying drawings and illustrations disclosing a preferredconstruction.

In the drawings:

Fig. 1 is an elevational view partly in section;

Fig. 2 is a section taken on the line 2 2 of Fig. 1;

Fig. 3 is an enlarged sectional view of a part of the outer portion ofthe compressor showing the outer shell, the separator rings, airdeflectors and impeller shrouds.

Referring specifically to the drawings in which like numerals indicatesimilar parts throughout the various views, the compressor is indicatedgenerally at 6, the same comprising a cylinder or shell 'l of a hightensile strength material and having identical head members 8 and 9,said members being welded as at l0 and Il to the cylinder 'l when thevarious units of the cornpressor are finally assembled. The cylinder orshell 1 is further provided adjacent its inner surface with a pluralityof cast deflector members or separators I2, I3, I4 ane. la therebydividing the interior of the compressor into respective chambers, theseparators being machined to flt in the cylinder and held in place as bydowels or set screws I6. The cast deflector members are further providedwith air diverters I1 which are formed as a pat of the separator rings.The separator rings are provided with downwardly extending flangeportions IB, I9 and 20 which form a portion which is in close runningcontact with the shroud parts 2| of the respective impellers 22 of thecompressor.

As will be seen the end portion 9 of the compressor has an air inlet 23and the respective impeller blades have air inlet openings 24 whichopenings conduct air through the impeller blades. pellers, the bladesbeing turned back upon themselves and discharging air against thedeilectors I2, I3, I4 and I5 and also against the air dlverters I1, theair traveling from the respective chambers to the next succeedingimpeller inlet and finally to the air outlet 24a.

Thus it will be seen that by having the respective impeller blades turnback upon themselves that the compressor can be made much smaller thanthose of known construction, and further the outer diameter of thecompressor is much reduced in size because of the arrangement of the airdefiectors and diverters, and because of which the air space can begreatly reduced in size.

The impellers are made as separate units and are mounted on a hollowshaft 25, the shaft lbeing provided with splines 26 which receivecomplementary recesses or key ways 21 formed in the hubs of theimpellers. The rotary shaft 25 carrying the impeller blades at its rearend is mounted in a bearing 28 held in place by a stud 29 extendingthrough a flanged portion 30 which is welded to the end 8. Adjacent thebearing 28 is a packing gland 3| to prevent oil and air leakage, thegland 3| being held in place as by a retaining member 32. At the otherend the shaft 25 is mounted in two bearings 33 and 34, the bearing 33being a roller bearing and being held in place by a stud 35 extendingthrough an extension 36 welded to the head 9. The other bearing 34, athrust bearing, is threaded as at 31 said threads engaging with threads38 on the inner surface of the extension 36. The bearing 34 is providedwith a key or tool socket 39 and the extension 36 is provided with aslot 40 whereby access may be had to the socket 39 to engage the same bya tool to move the bearing 34 toward and from a shoulder 4I saidshoulder being a part of the shaft 25, whereby the shaft, containing therespective impellers can be moved longitudinally to some extent, thusmoving the impellers to thereby vary the distance between the flanges 20of the air deflectors and the portions 2| of the impeller shrouds. Y

In the assembly of the compressor the shell 1 and the head 9 thereof areflrst assembled, the head 9 of course carrying the bearings 33 and 34.The shaft 25 is taken andthe first separator ring I5 moved over theshaft after which the flrst impeller is driven onto the shaft in tight tthere-- with, and successively each of the separator rings and itsassociated impeller is mounted on the shaft, this of course being donewhile the shaft and the respective elements are removed from the shellI1. Thus we have the shaft 25 with the respective units mountedthereabout. After this, the shaft with its impellers and separator ringsare pushed into the shell 1 whereupon the studs I6 are engaged in thecomplementary recesses in the respective rings to hold the same inplace. The head 8 with its bearing and stuffing box is then attached tothe shell 1 thereby completing the assembly.

The invention is not limited to the exact construction shown, but iscapable of variation within the scope of the following claims.

I claim:

1. In a radial compressor, the combination comprising a shell, heads onsaid shell, air inlet and discharge ports, bearings in the heads, ashaft mounted in the bearings, shrouded impellers mounted on the shaft,separator rings mounted within the shell and having downwardly extendingflanged portions being spaced in close proximity to the shrouds of theimpellers to form separate air pressure chambers, deflector bladesmounted on the separator rings, the surfaces of the separator rings andthe deflector blades tending to change the radial and circular flow ofair from the shrouded impellers and directing the same tangentially intothe surrounding space.

2. In a. radial compressor, the combination comprising a shell, heads onsaid shell, air inlet and discharge ports, bearings in the heads, ashaft mounted in the bearings, shrouded impellers mounted on the shaft,separator rings mounted within the shell, said rings having flangesextending downwardly within the air space and spaced in close proximityto the shrouds of the impellers to thereby form separate pressurechambers, and deflector blades mounted on the separator rings andextending inwardly in close proximity to the outer ends of theimpellers.

WARD T. MIXSELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 979.634 Akimoff Dec. 27, 19101,281,478 Antlsell Oct. 15, 1918

